Documents disponibles écrits par cet auteur

Compression triaxial behavior of concrete / Cedric Poinard in European journal of environmental and civil engineering, Vol. 16 Supplément N° 1 (Juin 2012) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 16 Supplément N° 1 (Juin 2012) . - pp. s115-s136 Titre : Compression triaxial behavior of concrete : The role of the mesostructure by analysis of X-ray tomographic images Type de document : texte imprimé Auteurs : Cedric Poinard, Auteur ; Ewa Piotrowska, Auteur ; Yann Malécot, Auteur Année de publication : 2012 Article en page(s) : pp. s115-s136 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  Triaxial  loading  X-ray  tomography  Porosity  Damage  mechanisms Résumé : This paper is intended to assess the mesostructural damage mechanisms of concrete under hydrostatic and triaxial loadings. Such a study is possible thanks to two state-of-the-art laboratory instruments: a high-pressure triaxial press, and an X-ray computed tomography instrument. The laboratory protocol consists of scanning the concrete prior to the initial loading and after each cycle. An analysis of the resulting images indicates that under high hydrostatic loading, significant damage is visible in cement paste at the mesoscopic scale. For two triaxial tests conducted at 50 and 650 MPa of confining pressure, results reveal major differences in both damage and failure mechanisms. At the lower pressure, shear loading creates a localised failure mechanism characterised by sliding on an inclined plane, whereas at the higher pressure, the strain and damage mode are much more homogeneous with a failure localisation after unloading. ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/full/10.1080/19648189.2012.682458 [article] Compression triaxial behavior of concrete : The role of the mesostructure by analysis of X-ray tomographic images [texte imprimé] / Cedric Poinard, Auteur ; Ewa Piotrowska, Auteur ; Yann Malécot, Auteur . - 2012 . - pp. s115-s136. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 16 Supplément N° 1 (Juin 2012) . - pp. s115-s136 Mots-clés : Concrete  Triaxial  loading  X-ray  tomography  Porosity  Damage  mechanisms Résumé : This paper is intended to assess the mesostructural damage mechanisms of concrete under hydrostatic and triaxial loadings. Such a study is possible thanks to two state-of-the-art laboratory instruments: a high-pressure triaxial press, and an X-ray computed tomography instrument. The laboratory protocol consists of scanning the concrete prior to the initial loading and after each cycle. An analysis of the resulting images indicates that under high hydrostatic loading, significant damage is visible in cement paste at the mesoscopic scale. For two triaxial tests conducted at 50 and 650 MPa of confining pressure, results reveal major differences in both damage and failure mechanisms. At the lower pressure, shear loading creates a localised failure mechanism characterised by sliding on an inclined plane, whereas at the higher pressure, the strain and damage mode are much more homogeneous with a failure localisation after unloading. ISSN : 1964-8189 En ligne : http://www.tandfonline.com/doi/full/10.1080/19648189.2012.682458

Concrete structures under impact / Daudeville, Laurent in European journal of environmental and civil engineering, Vol. 15 N° Spécial (Septembre 2011) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 15 N° Spécial (Septembre 2011) . - pp. 101-140 Titre : Concrete structures under impact Titre original : Structures en béton sous impact Type de document : texte imprimé Auteurs : Daudeville, Laurent, Auteur ; Yann Malécot, Auteur Année de publication : 2012 Article en page(s) : pp. 101-140 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  Impact  Triaxial  stress  Modelling  Empirical  formulae Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The upcoming need of concrete structures designed against impulsive loading such impact requires analytical treatments comparable to those existing for structures under static loading in spite of a poor state of knowledge of material behaviour in this range of loading. This paper first presents basic relations and empirical formulae used by civil engineers for the design of concrete structures under impacts. Experimental analyses of concrete behaviour under high triaxial stress and high strain rates show that empirical formulae have to be used with care. Some recent numerical developments are also shown. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16588 [article] Concrete structures under impact = Structures en béton sous impact [texte imprimé] / Daudeville, Laurent, Auteur ; Yann Malécot, Auteur . - 2012 . - pp. 101-140. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 15 N° Spécial (Septembre 2011) . - pp. 101-140 Mots-clés : Concrete  Impact  Triaxial  stress  Modelling  Empirical  formulae Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : The upcoming need of concrete structures designed against impulsive loading such impact requires analytical treatments comparable to those existing for structures under static loading in spite of a poor state of knowledge of material behaviour in this range of loading. This paper first presents basic relations and empirical formulae used by civil engineers for the design of concrete structures under impacts. Experimental analyses of concrete behaviour under high triaxial stress and high strain rates show that empirical formulae have to be used with care. Some recent numerical developments are also shown. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/article.jsp?articleId=16588

Strength and damage of concrete under high triaxial loading / Yann Malécot in European journal of environmental and civil engineering, Vol. 14 N° 6-7 (Juin 2010) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 14 N° 6-7 (Juin 2010) . - pp. 777-803 Titre : Strength and damage of concrete under high triaxial loading Type de document : texte imprimé Auteurs : Yann Malécot, Auteur ; Daudeville, Laurent, Auteur ; Fabrice Dupray, Auteur Année de publication : 2011 Article en page(s) : pp. 777-803 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Concrete  Triaxial  test  High  confinement  Mesoscale  modeling  Young's  modulus Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study focuses on identifying concrete behavior under severe loading (near field detonation or ballistic impacts). In order to reproduce high stress levels with wellcontrolled loading paths, static tests are carried out on concrete samples by mean of a very high-capacity triaxial press. Experimental results indicate a sizeable change in concrete behavior with confining pressure. At low pressure values, the concrete exhibits brittle behavior with failure caused by a localized damage mechanism. In contrast, at high confining pressures, the concrete becomes a ductile material, and failure is associated with diffuse material damage. These tests also show an evolution of the elastic characteristics of concrete. A numerical modeling of these previous experiments is performed at a mesoscopic scale. It provides a reproduction of the main characteristics of concrete behavior under high confinement, both qualitatively and quantitatively. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp [article] Strength and damage of concrete under high triaxial loading [texte imprimé] / Yann Malécot, Auteur ; Daudeville, Laurent, Auteur ; Fabrice Dupray, Auteur . - 2011 . - pp. 777-803. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 14 N° 6-7 (Juin 2010) . - pp. 777-803 Mots-clés : Concrete  Triaxial  test  High  confinement  Mesoscale  modeling  Young's  modulus Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This study focuses on identifying concrete behavior under severe loading (near field detonation or ballistic impacts). In order to reproduce high stress levels with wellcontrolled loading paths, static tests are carried out on concrete samples by mean of a very high-capacity triaxial press. Experimental results indicate a sizeable change in concrete behavior with confining pressure. At low pressure values, the concrete exhibits brittle behavior with failure caused by a localized damage mechanism. In contrast, at high confining pressures, the concrete becomes a ductile material, and failure is associated with diffuse material damage. These tests also show an evolution of the elastic characteristics of concrete. A numerical modeling of these previous experiments is performed at a mesoscopic scale. It provides a reproduction of the main characteristics of concrete behavior under high confinement, both qualitatively and quantitatively. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp